Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 168 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
3. 3.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 8 HIGH
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
4. 4.🔁 count = 10
   repeat 5 times { count = count + 4 }
   What is count at the end?
5. 5.⚙️ Which actuator would you use to show a status light? (a) a servo motor (b) a pump (c) a motor (d) an LED
6. 6.📶 A pin that reads a push button is set as … (a) an output (b) an input (c) a resistor (d) a battery
7. 7.🔐 Is it a good or a risky habit to turn off unused gadgets? (a) risky habit (b) good habit
8. 8.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) none (c) one (d) two
9. 9.Which of these is the output? (a) a motion sensor signal (b) decide if soil is dry (c) compare with a limit (d) a buzzer beeps
10. 10.🤖 “if (A AND B)” is true when … (a) only A is true (b) both are false (c) both A and B are true (d) only B is true
11. 11.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) light-emitting diode (d) low energy device
12. 12.🔍 Which is the odd one out? (a) set a strong password (b) share camera links (c) tap unknown app links (d) keep factory passwords
13. 13.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 85000 Ω resistor? (a) grey-green-orange (b) grey-green-yellow (c) green-grey-orange (d) grey-green-red
14. 14.What does a diode do? (a) has coloured bands (b) smooths a wobbly supply (c) lets current go one way (d) turns a fan or wheels
15. 15.🔍 Which sensor would you use to switch on lamps at dusk? (a) a distance sensor (b) a temperature sensor (c) a light sensor (d) a rain sensor
16. 16.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to limit the current (d) to change its colour
17. 17.📏 How many kilowatts (kW) is 1550 W? =
18. 18.Which job is done by the reset button? (a) runs the program (b) brings power and code (c) restarts the program (d) connect sensors and LEDs
19. 19.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) gets bigger (d) becomes zero
21. 21.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V ÷ I (d) R = V × I
22. 22.🔌 Is a steel spoon a conductor or an insulator? (a) an insulator (b) a conductor
23. 23.💡 2 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulbs 1 and 2 are taken out of their holders. How many bulbs glow?
24. 24.🔘 Which kind of switch stays where you flip it? (a) a push button (b) a slide switch (c) a reed switch (d) a toggle switch
25. 25.🔁 x = 4
    repeat 4 times { x = x × 2 }
    What is x at the end?
26. 26.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 400 ms }
    How many times does the LED blink in 3 seconds?
27. 27.🌈 In the resistor colour code, which number does black stand for?
28. 28.🔌 Which metal is used for most electric wires at home? (a) plastic (b) rubber (c) glass (d) copper
29. 29.True or false: a woollen thread is a conductor. (a) False (b) True
30. 30.✏️ In a circuit diagram, which part is drawn as a circle with V inside? (a) cell (b) voltmeter (c) switch (d) bulb
31. 31.True or false: to use a cable with cuts is safe. (a) True (b) False
32. 32.True or false: “one out, the rest glow” is true of a parallel circuit. (a) True (b) False
33. 33.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) type it all in (b) share it with friends (c) ask a parent first (d) post it online
34. 34.Which job needs a rain sensor? (a) open blinds at sunrise (b) close a window in rain (c) switch on lamps at dusk (d) water a dry plant
35. 35.🔁 What does a variable do in a program? (a) blinks an LED (b) joins two wires (c) stores a value (d) measures light
36. 36.⚠️ Why must we never touch switches with wet hands? (a) water carries current (b) it is just untidy (c) water makes it cold (d) it spoils the paint
37. 37.Which of these mainly makes sound? (a) an electric kettle (b) a siren (c) a torch (d) a water heater
38. 38.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
39. 39.🌐 Each reading a sensor sends is 50 bytes. How many bytes do 100 readings take?
40. 40.🔐 Why install updates on IoT devices? (a) they delete the Wi-Fi (b) they change the colour (c) they fix security holes (d) they make it heavier

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